Hydraulic vibration and shock absorber



" May 18, 1943 c. HUS$MAN HYDRAULIC VIBRATION AND 5500K ABSORBER FiledNov. 7. 1941 //v VE/VTOR an R1. HUM/VAN Patented May. 18,

t. UNITED STATES PATENT .oFFicE HYDRAULIC AND SHOFK I Carl Hussman,Chicago, 111.

Application November 7, 1941, Serial No. 418,110

7 Claims. loner-1) This invention relates to vibration and shockabsorbers and has reference more particularly to absorbers in which. ahydraulic fluid is used for absorbing shocks.

In submarines, it has been found desirable to support the propellingengines on anti-vibration bases or mountings, so as to prevent unduevibration of the hull. However, it has been found that when a submarineis attacked with depth bombs, the engines are apt to tear loose fromtheir antivibration mountings, with the result that the submarine-isunable to escape from the attacking which shocks are absorbed whenoriginating either above or' below the engine; also to improve enginemountings in other respects hereinafter specified and claimed.

mounting.

Referring to the drawing by numerals, a pair of rigid spaced platesinclude a base plate 10 arranged to be attached to a floor through boltholes II, and a platform plate l2 arranged to be bolted to the base ofan engine through bolt holes 13. A cylinder or chamber is secured, as bywelding to the bottom face of plate I 2, and a larger cylinder orchamber I5 is secured to the upper face of plate the two cylinders beingconcentrically or telescopically arranged. A

heavy spiral spring I6 is positioned in the cylinder 13 and between theplates I 0 and 12. Nonmetallic washers l1 and 18 separate the .endsofspring 13 from plates Ill and I2 respectively, so as to protect saidwashers.

vibration through the spring. A non-metallic ring packing 20 extendsbetween the cylinders l4 and I5 and the lower edges 21 of cylinder 14are slightly rounded to permit said cylinder id to move freely axiallyin space 22 between the ring 20 and washer 11. Steel bearing plates 23and 24 extend between washers l1 and 10 respectively, A central airventing hole 25 extends through plate 24 washer I8 and plate-l2 so thatthe space above spring i6 is open to the atmosphere at all times.

A ring 21 or other projection, is secured by Welding to the outsideofcylinder i4 about midway its ends, the outer diameter of said ring 21being such that an annular space 28 is provided between said ring 21 andthe cylinder 15. A

helical spring 29 is positioned between cylinders 14 and 15 below thering 21, the lower end of said ring resting on a ring bearing plate 30which is supported on the packing ring 20. A helical spring 31 ispositioned between cylinders l4 and 15 above the ring 21. An annular cap32 extends above the cylinder 15, a clearance space 33 being providedbetween the inner edge of cap 32 and the cylinder H. A downwardlyextendingannular flange 33 fits closely around the upper end of cylinderi5 and locking tap bolts 35 pass radially through the flange 34 and arethreaded into the cylinder IS. A non-metallic packing ring 38 sur-Reference is to be had to the accompanying rounds the cylinder ll belowthe cap 32 and a metal bearing ring 31 extends between the upper toprevent the transmissionv of high frequency end of spring 3| and ring36.

A heavy asphalt 39 or other suitable semi-solid material is preferablypoured hot in the space in cylinder 14 around the spring I and whensolidified, the asphalt prevents the transmission of high frequencyvibrations through the spring H5, at the same time permitting lowfrequency vibrations of the spring I 8 under the influence of a movingmachine supported on the platform l2. A

heavy petroleum oil 40 or other suitable liquid is poured into the spacebetween cylinders I3 and 15 around the springs 29 and 31. movable partsl2, l4 and 21 vibrate vertically under the influence of the supportedengine or other machine, the liquid 43 surges back and forth through theopening 28. In case of a shock on platform 12 such as thatresulting fromthe explosion of a depth bomb, the space 28 so restricts the flow ofliquid that the movement of the platform I2 either up or down isgradually retarded or dampened until the force is spent.

' This retarding action is such that the engines of As the verticallyings and the submarine has a good chance of escaping from the attackingvessel. If the depth bomb explodes above the submarine, the liquid II incross-section so that the coils contact one with the other if the shockis exceedingly severe soas to'act as a final limiting stop to themovement of platform l2.

The device as described above incorporates two features,- (1) eifectiveisolation of machinery vibrations and (2) complete absorption of shockdue to depth bombs, collision or other emergencies. A device about twicethe size of that illustrated, is capable of carrying a machinery load upto 1500 lbs. with a natural frequency of the spring system of 2.6 cps.minimum. 'As a shock absorber, it is capable of absorbing a force of ablow equal to or greater than that which it would experience in anactual installation, if the platform I2 is accelerated at a rate of 15g. In this case, the

force acting on the platform I! is fifteen times the supported mass, or22,500 lbs. This force may be applied vertically in both directions, orin any direction at an angle of as much as 50 from the vertical. Thebolts 35 provide for assembly in partial compression of the spring I8.Partial re-.

moval of the bolts 35 allows dismantling of the device for inspection,replacement and repair of all parts.

The device is particularly advantageous in action as it combines ahighly eflective shock absorbing feature with a maximum degree of vibration isolation. The vibration isolation is accomplished by saidplatform.

(1) The proper deflection of springs l6, and I 3| effecting a naturalfrequency of 2.6 cps.

(2) By submerging said springs in liquids of selected and properconsistency and composition for the desired degree of damping.

(3) By isolating all springs with composition pads, properly compressed,to prevent the w 1 of high frequency vibrations. I

(4) By avoiding all metal contact between the movable andstationary'parts.

cured to the other of said plates and surrounding said first cylinder, aliquid filling the space between said cylinders, and means associatedwith said cylinders for causing said liquid to surge through arestricted opening so as to damp the movementof said vibrating plateswhen a shock is imposedon said vibrating plate.

2. In a device of the class described, a pair of spaced, substantiallyparallel members, a pair of telescopin nders between said members,vibration absorbing springs within and between said cylinders, a liquidconfined between said cylinders, one of said cylinders being movablewith one of said members, a projection secured to said movable cylinderand spaced from said other cylinder, and means for causing said liquidto surge through said space when said movable member is moved by ashock, said liquid serving to damp the movement of said movable member.

1 3. In an anti-vibration shock absorber, a base, a platform in spaced,parallel relation to said base, a cylinder extending from said platformtoward said base, a second cylinder telescoping with said first cylinderand extending from said base toward said platform, a vibration absorbingspring between said platform and base within said first cylinder, a ringextending from said first cylinder toward said second cylinder andspaced apart from said second cylinder, and aliquid between saidcylinders arranged to surge through said space when a shock is appliedto said platform, so as to damp the movement of 4. A device as describedin claim 3 characterized by anti-vibration springs on each side of saidA device as described in claim-3 characterized by non-metallic packingmembers between said springs and metallic parts of said assembly so asto prevent the transmission of high frequency vibration through saidsprings.

I would state in conclusion that while the example illustratedconstitutes a practical embodiment of my invention; I do not wish tolimit myself precisely to these details, since, manifestly the same maybe considerably varied without departing from the spirit of theinvention as defined in the appended claims.

Having thus described my invention, I claim as new and desire to secureby Letters Patent:

6. A device as described in claim 3 characterized by a semi-solidmaterial surrounding said spring so as to prevent high frequencyvibratio from passing through said spring.

'1. .In a .device of the class described, a pair of plates in spaced,parallel relation, telescoping cyl- 1 inders extending inwardly fromsaid plates to form a chamber therebetween, a liquid in said chamber,one of said plates and cylinders being 'movable and the other of saidcylinders being 1. In a device of the class described, a pair of platesin spaced parallel relation, a helical spring between said plates forabsorbing vibrations imposed on' one of said plates, a semi-solidmaterial fixed, a projection extending from said movable cylinder towardsaid fixed cyginder, said projection being spaced-apart a predetermineddistance from said fixed cylinder to form a restricted fiow space, aliquid in said chamber arranged to surge through said restricted spacewhen a shock is imposed on said movable plate, anj anti-vibrationsurrounding said spring for absorbing high ire-' quency vibrationsimposed on one of said plates,

a cylinder secured to said vibrating plate and surrounding said spring,a second cylinder sespring associated with said plates and cylinder,

,and a cap over one of said cylinders and loosely fitting about theother of said cylinders, said cap forming a seat for an anti-vibrationspring.

